A strut bar, or commonly known as a strut brace or a strut tower brace, is designed to tie the two opposing strut towers together to form a single unit. This is to minimize the strut tower flex during hard cornering.

When taking a turn, a car's strut towers normally flex. This may cause the losing of some traction. The strut tower brace keeps the strut towers from flexing. They distribute the pressure applied to one strut tower when taking a turn on both towers instead of just one.

This results to improved chassis rigidity. Understeer is reduced, the tire wear is improved and metal fatigue is minimized in the strut tower portion. Adding a brace between these two strut towers is a great way to solidify a vehicle's suspension.

The purpose of the roll bar is to protect driver and passengers from injury if the car rolls over onto its roof. A series of tubes that are welded together into a contoured shape, and then bolted directly to the frame members, or rails. Since frame members are located differently on different types of cars, a roll bar is very unique to an individual car, and must be designed for a specific car. Although a roll bar is a very nice feature, it is not always practical, because there isn't a place to mount it. Roll bars are usually put on convertibles as an aftermarket add-on piece. A convertible provides no protection if it overturns. Some cars have built-in "targa" roll bars. These are roll bars that are covered up by body work; they appear to be part of the body. Targa roll bars are generally flat and wide, instead of round like normal roll bars. Because they are wider, they are able to hold up the overturned car. They also look nice, because they look like a body panel. They do reduce rear visibility because of their greater width. Some targa roll bars are purely cosmetic, because they have no frame inside. This type of roll bar affords you about as much protection as the windshield, and so is not really a roll bar. Most cars don't come with roll bars, but all race cars have roll bars. Roll bars themselves are relatively inexpensive, but they usually require quite a bit of expensive installation work. Some roll bars provide better protection than others. If you have a tendency to exceed the speed limit along winding roads or go off roading, you really ought to have a roll bar.